Truss Composite Ceiling with Little Amount of Steel

ABSTRACT

Joists designed to be used as roof cover in the form of composite ridge in different buildings of residential, commercial and official types and can be generalized to pre-fabricated shear walls. Simplification of their execution process at the construction stage accelerates roof execution and reduces the need for using costly equipment. On the other hand, the existence of installations under the roof reduces the costs of pavement and environmental pollutions decrease due to lighter roof and structures and due to the utilization of less construction materials.

BACKGROUND OF INVENTION

In composite roofs, the whole load of the roof is held up by steel beams which requires, making use of weighted steel beams, which itself increases the cost significantly.

In the common composite roofs, in order to connect the roof beams with concrete over it, shear connector had to be used. This is both time consuming and would increase the cost. In order to resolve this issue a new system was designed.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1, shows the structural features of the current invention

FIG. 2, is an enlargement of U-shaped piece 1

FIG. 3, displays different connection of the roof

FIG. 4, displays different connection of the roof

FIG. 5, displays different connection of the roof

FIG. 6, the joists and beams

FIG. 7, displays parts 5 and 6

FIG. 8, displays the middle sheet

FIG. 9, displays connection between parts 3, 5 and 6

FIG. 10, displays different connections of joists

FIG. 11, displays another view of the invention

FIG. 12, displays grooves and side parts

FIG. 13 displays longitudinal grooves

FIG. 14, displays the construction process

FIG. 15, displays the installation process

FIG. 16, displays the molding of the roof

FIG. 17, displays the roof reinforcement

FIG. 18 displays the method via which the joists are installed in the roof structure

SUMMARY OF INVENTION

In the designed roof, the load bearing capacity of the concrete is used in the joists which decreases the required amount of steel. Since, the installation pipes may pass from beneath the roof and through the existing holes in the roof joists, the pavement may be lighter. Also in the designed roof, due to the merging that happens between the concrete and the roof joists, there is no need for a shear connector.

The joists designed, not only eliminate the overload but also decrease the need for utilizing steel in the roof. Elements of the designed roof are major and play a structural role. They do not impose any excess load, and they need no permanent molds. This is achieved through utilization of formed steel sheets that increases the inertia moment and ultimately due to the gyration radius, less steel provides more resistance.

Most importantly, since the trusses are completely made in the factory considering its special design, the human errors decrease significantly. The designed joist was tried to have a higher capacity of load bearing by the steel, and this has been achieved through special steel sheets forming. It is not merely the sheets thickness that is taken into account for increasing the load bearing capacity, rather, it is through forming of the steel sheets that inertia moment and the gyration radius are increased and as a result the steel functions more efficiently for the purpose of load bearing compared with the existing roofs.

In the designed joist, the load bearing capacity of the concrete allows the roof joists to bear the roof load, which usually imposes less expense compared with steel. Due to the special form of the roof joists which are composed of cold formed sheets, the concrete used in the designed joist is completely mixed with the roof joists to make a consolidated structure which needs no shear connector. This reduces the cost and allows faster execution and even when the roof is composite, it can be executed easily with concrete and metal structures.

In the designed joist, all elements are designed in a way that they cannot be put anywhere but their main place and this eliminates the risk of human error.

The joist may be produced from steel or galvanized sheets and bolt is used to connect the members, which allows faster execution at the construction stage.

However, the most important privilege of this joist, is that it is environment friendly. The lighter structure of the joist and the lower amount of materials used in its production, significantly decreases the need for fossil fuels and natural resources. Moreover, it is noteworthy that because of its special form, the joist makes it possible for the installation pipes to pass underneath the roof and this reduces the pavement cost.

The designed joist can also be used in the shear walls the execution of which is accomplished using galvanized or steel sheets instead of beam and molding, reinforcement and mold opening stages will all be eliminated considering that the designed wall plays not only the role of a mold but also decreases the execution speed.

The joists are made of cold formed steel sheets and the parts are linked together by bolt. The special form of the joists allows the concrete to penetrate into the joists made of cold formed sheets and the composite joists make a consolidated part being combined with the roof slope and there is no need to join them with shear connector. The elimination of beams and making use of cold formed steels in combination with concrete in a new form, allows elimination of shear connectors and without them, steel sheets and concrete become merged.

An important point to remember in the designed joists, is the method based on which the cold formed sheets are combined with concrete and become consolidated needing no shear connector. This privilege in addition to the new design of the roof and the way the cold formed steels become consolidated with concrete is a novelty.

LIST OF ELEMENT NUMBERS

-   -   1 Is a U shaped cold formed steel, and is put underneath the         joist and the bottom chord forming the truss joist being         combined with concrete     -   2 Is an enlargement of U-shaped steel, to display the hollow         space     -   3 Sheets cut in the shape of “S” and formed to be used in the         edges (S-shaped sheet)     -   4 Grooves made in the S-shaped sheet to improve the rigidity and         to allow easy installation     -   5 Sheets formed like a triangle to be placed in the middle of         the joists between parts of S-shaped sheet (triangular sheets).     -   6 Sheets formed like FIG. 5, except that, the part underneath         part 6 is somewhat sloped upwards to allow penetration of         concrete from beneath, similar to what displayed in FIG. 10.     -   7 Edges of FIGS. 5 and 6 are bent outwards with a 90 degree         angle.     -   8 In the middle of FIGS. 5 and 6, hollows are created all around         to allow easy exit of concrete bubbles     -   9 The upper formed sheet that is installed in the upper part     -   10 The slope of the beneath part of FIG. 6     -   11 The bolt connecting parts to one another     -   12 Hollows at the wall of U-shaped sheet     -   13 The longitudinal bent beneath FIG. 1     -   14 Completed joist     -   15 Part at joist support     -   16 The joist produced to be used without concrete     -   17 Details about placing mesh network and execution of beams         cover on the top of upper sheet.     -   18 Execution of joists over the structures     -   19 Execution of the first stage of formwork     -   20 Enlargement of stage 1 of formwork to show the way mold parts         pass through the joist holes.     -   21 Execution of the second stage of the formwork     -   22 Mesh works of the roof     -   23 Concrete works of the roof     -   24 Mold opening     -   25 Structural load bearing beams     -   26 Short four sided scraped woods to be passed through         triangular sheets and 6     -   27 Long four sided scraped woods to be executed on parts 26     -   28 Mold plates     -   29 Reinforcement     -   30 Knee for execution of mesh network cover     -   31 Mesh network covering     -   32 Roof concrete     -   33 Formwork enlargement     -   34 Enlargement of roof concrete work and that of the concrete         inside the joists     -   35 Components of the second joist     -   36 Second-type designed joist     -   37 Consists of S-shaped sheet and 9     -   38 Is a substitute for parts 6 and triangular sheets

DETAILED DESCRIPTION OF SPECIFICATION

As illustrated in FIG. 1, the invented joist consists of various parts each fastens to other parts to make a robust consolidated product. The following details make this clear:

1: U-shaped steel is made of galvanized or steel sheets cut first hand in the form of stripes by the rolling device and are next formed by roll forming devices like FIG. 1 to be shaped like “U”. As it is observed in the enlargement of FIG. 2, to allow higher degree of rigidity, some longitudinal grooves are made at the bottom of this part, displayed in FIG. 13, and between the grooves and at the side parts, some hollows are made like FIG. 12. This not only enhances the rigidity but also allows the joist to be entangled with the concrete and also allows the steel sheets—concrete adherence.

2: is simply U-shaped steel that is enlarged in FIG. 2. It has three parts. Part a₁ lays in a horizontal axis and has two triangular notches marked 13 (later will be described in details). Two other parts include edges b₁ and c₁ bent with a 90-degree angle and lay over a₁.

U-shaped steel is made of galvanized and steel sheets firstly cut by the rolling device in the form of stripes and next made into a U-shape as illustrated in FIG. 1 by the role forming device. As shown in the enlargement of FIG. 2, more consolidation and robustness is achieved by putting longitudinal grooves illustrated in FIG. 13, underneath the U-shaped steel and in a₁. Between these grooves, the part illustrated in FIG. 13 is devised and some notches are made on edges b₁ and c₁ in a zigzag way with a 45-degree angle along the joist, just as it is seen in FIG. 12 and these notches are made at the both ends of the external part of iron joist 1. These notches visible in FIG. 12, have inward inclination. These notches not only enhances the involvement of the joist with the concrete but also provides a proper adherence between the steel sheets and the concrete.

The invention has different parts that their placement beside one another enhances the robustness. The above invention has many different parts that by being placed beside each other caused increasing robustness. It is explained more in the following.

S-shaped sheet 3: Side parts are cut to the form of “S”, so that they form the diagonal elements of the truss joist beside each other.

After that the parts number 3 are cut to the desired shape from the steel or galvanized sheet according to the Figures, its notch is created in the middle of it, Parallel to the length of the S-shaped sheet around the designed area as cold-rolling like what it is seen in FIG. 4, that will increase the robustness of this section. This notch is toward the joist inside. The S-shaped sheet is installed beside the truss joist and between triangular sheets and section number 6, and then U-shaped steel from below and section number 9 from above are connected to it by the bolts.

The triangular sheets and 6 as shown in FIG. 1 are placed among diagonal S-shaped sheet. The triangular sheets and 6 are in the shape of triangle that have two edges in two ends of them as the FIG. 7. These edges as they are shown in the figure, has the larger cross-sectional area than the triangle and are in the shape of triangle. As it is shown in the figure, the edges number 7 are being bent with 90 degree angle outward and perpendicular on the triangular sheets and 6 so that the S-shaped sheet are place behind these bent edges and are joint to each other.

The purpose of bending of edges of triangular sheets and 6 in the form of 90 degree as FIG. 7 outward is providing the required space for fastening the bolt and the required junctions with the U-shaped steel and S-shaped sheet and 9.

To exit concrete air shed inside the joists in the triangular sheets and 6, two parallel notches are created around its external environment and toward the triangle inside that is shown in FIG. 8, it means that the created notch is seen salient from the created holes. In addition to the facility of exodus, the concrete air caused more robustness.

The holes created in these triangles (triangular sheets and 6) for temporary formworks are used for the purpose of concrete pouring and to allow the installations pass from beneath the roof. As it is displayed part 26 passes through triangles triangular sheets 5 and 6 for the purpose of formwork. Moreover, the edge of FIG. 5 is bent outwards with a 90 degree angle like FIG. 7, to provide the space required for bolt fastening and to allow connection to U-shaped steel, S-shaped sheet and 9.

Part 6 is just the same as triangular sheets 5, except that, its bottom has an upward slope like FIG. 10 in order to allow the concrete penetrate into its bottom.

The triangular sheets 5 and 6 that almost have a triangle form are made of rectangular galvanized or steel sheets and are formed as displayed in FIGS. 5 and 6. The sheet slit can be filled with strip through welding. In the middle of these sheets, there are grooves the depths of which are displayed in FIG. 8. These enhance the rigidity of the sheets and provide a canal for the concrete bubbles to exit.

The triangular sheets 5 and 6 can also be designed with a circular section. In this case, the parts will be of a cylindrical shape instead of triangular. However, it is better to make them with a triangular form to allow higher degree of rigidity and to allow them function as a truss. Moreover, when these parts are made in the form of triangle, galvanized/steel sheets wastes will be less when producing the S-shaped sheet. However, having a cylindrical shape, they allow easier penetration of concrete into the bottom of the joists, yet the environmental pollutions will be of a higher degree because of the wastes.

The S-shaped sheet 3, triangular sheets 5 and 6 are the first connected to one another by bolt. Afterwards, U-shaped steel is placed underneath, and part 9 is placed above and they are connected to each other by bolts like FIG. 11. A machine can also be designed to connect all parts to one another by bolt simultaneously

9—Cold formed steel sheets are installed as the top chord of the joist. Parts of number 9 designed in a way to allow temporary molds be placed beneath it properly. Parts of number 9, are made of galvanized or steel sheets which are cut in the form of strips and formed by roll forming tools as displayed in FIG. 9. The enlargement of FIG. 17 displays the details of part 9 and the way the roof beams are placed over it. As it is displayed in FIG. 17, the edges of part 9 on the top are formed in a way that they provide the required cover for the roof beams just like what is displayed in the Figures. However, the edge of part 9 can also be bent with a 90 degree angle and the required cover may be provided via other methods.

It is advisable to form and design part 9 in a way to not only enhance the part resistance but also provide the cover without using other sections. This allows faster execution and eliminates the additional costs like those incurred due to applying other parts such as spacer. Just like U-shaped steel, it is possible to create hollows in part 9, like FIG. 12. This provides a higher degree of adherence between the sheets and concrete.

U-shaped steel can be used in place of part 9. It can be placed in an upside down way and symmetrically on the top of the joist, just like FIG. 16. This is useful when you want the joist to be applied in the structure without concrete and just as a formed galvanized/steel sheet. Moreover, from the section number 16 also be used as a column to be used both without concrete and being composed with concrete.

In the construction process, part 9 is the last to be added to U-shaped steel, S-shaped sheet 3, triangular sheets 5 and 6 which have already been connected to one another. After adding it, the construction process is completed as is displayed in FIG. 14 and the joist is ready to be used for roof execution. At the two ends of the joist, at a point where the joist is supported, a piece is installed like FIG. 15, to be filled with concrete. This eliminates the shear force at the point of support.

FIG. 18 displays the method via which the joists are installed in the roof structure. First of all, the produced joists are placed over the load bearing beams of the structure No 25 at a certain gap from one another.

When the joists are installed at their own place (over parts with number 25), the roof formwork begins. For this purpose, the holes that exist in triangular sheets 5 and 6 can be used to allow parts with number 26 pass through them like what is displayed in the enlarged FIG. 20.

At first, parts 27 and 28 are connected to one another and beneath the roof, joists are put immediately beside parts of number 9. Next, parts with number 26 pass through triangular holes of triangular sheets 5 and 6 to fix parts 27 and 28 at their place.

29—The roof reinforcement is executed after the formworks, being supported by the top of the parts 9, as displayed in details in FIG. 17.

32: The roof concrete

After reinforcement (parts 29), the concrete works of the roof begins. After execution of concrete and when the concrete is hardened, the molds are opened like FIG. 16. To open the molds, first of all, parts with number 26 are removed from the holes. This allows parts 27 and 28 to be released and ultimately the mold is separated from the roof.

FIG. 17 illustrates the placing method of the roof molds. It is clear that the joists must be filled with concrete. FIG. 18 displays the roof following to concrete pouring. It shows after the concrete work of the roof, the concrete penetrates into the joists and allows the concrete of the roof slope, and that of the joist and the beam displayed in FIG. 14, function as a consolidated part.

For the construction facility, the designed joist is suggested that its construction process is easier than the joist number 14 and for its construction it's enough instead of section number 9 and S-shaped sheet in joist number 14, the steel sheet is formed and cut to be placed beside the section number 38 which will be explained and be placed in junction with section number 1 and the joist be completed.

U-shaped steel in this joist like the joist of FIG. 14 has the same performance but the section number 37 is replaced with section number 9 and S-shaped sheet and instead of constructing sections S-shaped sheet and 9 separately, the section number 37 will be constructed wholly and will be replaced with sections S-shaped sheet and 9.

According to the form of section number 37 which is replaced with sections S-shaped sheet and 9, section number 38 is placed instead of triangular sheets 5 and 6 in the form that can be able to be placed beside section number 37 and in junction with U-shaped steel that joint the sections by the bolt number 11. 

1- A truss composite ceiling comprising: A U shaped cold formed steel having saw tooth shaped projection in each of said U-shaped steel; multiple triangular shaped sheets creating hollow prisms; multiple S-shaped (or Z shaped) steels; wherein two of said S-shaped sheets are placed between and connect each of said triangular prisms to each other; wherein each of said neighboring prisms are placed in matching angle, where their respective bases are parallel and away from one another, and said prisms are extended at each end having an edge capable of holding each one of said S-shaped sheets in place; and wherein each of said neighboring S-shaped sheets attached and matched to said edge of said one prism are mirror image of one another; said S-shaped sheets, each comprise a matching indentation to said saw tooth projections, where they fit and match said saw tooth projections when placed next to each other. 2- The truss structure of claim 1, wherein said prisms comprise two parallel indentations going around an outer surface of said prism, where they room two V-shaped fixation pieces having a length similar to said U-shaped steel and fixedly keep all of said prisms and their matching S-shaped steels in place and create a slide and a singular structure together. 3- The truss structure of claim 2, wherein said U-shaped steel further comprises two triangular projections on a bottom surface, matching said two parallel indentations of said prisms. 4- The truss structure of claim 3, wherein said two V-shaped fixation pieces comprise two bended edges on either side that fit said two parallel indentations of said prisms on one end and has a longer edge on its other end that fits tightly next to said U-shaped steel covering said multiple prisms and S-shaped sheets. 5- The truss structure of claim 4, wherein said structure further comprises a second U-shaped steel covering said two fixation V-shaped pieces and is parallel to said first U-shaped steel. 6- The truss structure of claim 5, wherein said ceiling further comprises multiple beams, each passing through said hollow prisms creating a meshed structure of said ceiling. 7- The truss structure of claim 6, wherein said meshed structure is covered with mold plates on top and bottom, and filled with reinforcement material. 8- The truss structure of claim 7, wherein said reinforcement material is further covered with roof concrete. 